JP2008149326A - Laser cladding apparatus for valve seat portion - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately and excellently carry out a required laser cladding treatment for respective valve seat portions without being affected by thermal deformation, etc. <P>SOLUTION: A laser cladding apparatus 10 comprises a carrying and driving mechanism 28 which supports a cylinder head 12 and carries its respective valve seat portions 16a to a treatment position to be irradiated with a semiconductor laser beam 22, and can turn about the centers of the treating surfaces of the respective valve seat portions 16a, an image capture mechanism 30 for picking-up the image of the valve seat portions 16a to be arranged at the treatment position, and a control mechanism 32 which processes the image picked-up by the image capture mechanism 30, and calculates the positions of the picked-up valve seat portions 16a, and can adjust the positions of the valve seat portions 16a based on the calculated result. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a laser build-up device for a valve seat portion that supplies metal powder to a valve seat portion of a cylinder head and melts and solidifies the metal powder by irradiating the metal powder with laser.

  Usually, in the cylinder head constituting the internal combustion engine, the valve is repeatedly in contact with the valve seat portion. For this reason, the valve seat portion is required to have wear resistance. For example, a cylinder head made of an aluminum alloy employs a configuration in which a sintered ring is press-fitted into the valve seat portion.

  On the other hand, a laser cladding apparatus (so-called laser cladding apparatus) is used in which metal powder is supplied to the valve seat portion and is melted and solidified by irradiating the metal powder with a laser to build up.

  In this type of laser cladding apparatus, it is necessary to rotate the cylinder head around the axis of the valve seat portion in a state where the processing target surface is kept horizontal in the valve seat portion of the cylinder head. Therefore, a cylinder head support device is employed in which the cylinder head is mounted on the mounting table and the mounting table can be rotated around the axis of the valve seat portion.

  At that time, the cylinder head is once removed from the mounting table each time the valve seat portion of the cylinder head is subjected to the overlaying process. And the valve seat part processed next is positioned in the build-up processing position, and the operation | work which fixes a cylinder head to a mounting base again is performed. For this reason, the overlaying process with respect to each valve seat part is complicated.

  Therefore, in the cylinder head support device disclosed in Patent Document 1, a cylinder head mounting table that supports the cylinder head so that the processing target surface of the valve seat portion to be processed is substantially horizontal, and the mounting table described above. Rotation drive means for rotating around the rotation axis and supporting the valve seats movably along a straight line in which the valve seat portions are arranged and selectively rotating the mounting table around the rotation axis; Positioning means for selectively positioning the mounting table with respect to the rotation driving means so that the axis of the valve seat to be processed is aligned with the rotation axis.

  Thereby, it is not necessary to repeatedly attach and detach the cylinder head with respect to the mounting table, and all valve seat portions arranged along a straight line can be efficiently processed.

Japanese Patent No. 2929785

  By the way, in the above-described overlaying process, the laser is directly irradiated to the cylinder head, so that the cylinder head is likely to be thermally deformed. For this reason, there exists a possibility that the position of each valve seat part may fluctuate.

  However, in Patent Document 1 described above, even if the mounting table on which the cylinder head is mounted is positioned corresponding to each valve seat portion, the valve seat portion is mounted accurately with respect to the actual build-up processing position. May not be. Thereby, the problem that the overlaying process of a valve seat part is not performed with high precision is pointed out.

  The present invention solves this type of problem, and is not affected by thermal deformation or the like, and is capable of performing a desired build-up process on each valve seat portion with high accuracy and goodness. An object of the present invention is to provide a laser overlay apparatus.

  The present invention relates to a laser build-up device for a valve seat part that fills the metal powder by melting and solidifying it by irradiating the metal powder with a laser while supplying the metal powder to the valve seat part of a cylinder head.

  This laser build-up device supports a cylinder head, conveys each valve seat part to a processing position where a laser is irradiated, and is capable of rotating about the center of the processing surface of each valve seat part as a rotation axis. An image pickup mechanism for picking up an image of the valve seat portion disposed at the processing position, image processing of a picked-up image by the image pickup mechanism, calculating a position of the picked-up valve seat portion, and based on the calculation result And a control mechanism capable of adjusting the position of the valve seat portion.

  Further, the mounting drive mechanism selectively moves each valve seat portion provided on the cylinder head as a processing position by moving the mounting table on which the cylinder head is mounted at a predetermined angle and the mounting table. It is preferable to include a moving table disposed on the rotating table and a turntable capable of rotating the moving table.

  Furthermore, it is preferable that the imaging mechanism includes an illumination unit that irradiates illumination light to a valve seat unit that is irradiated with a laser, and a solid-state imaging device that images the valve seat unit disposed at a processing position.

  Furthermore, it is preferable that the solid-state imaging device is disposed on an extension line of the rotation shaft of the mounting drive mechanism.

  In the present invention, when the valve seat portion arranged at the processing position is imaged by the imaging mechanism, the captured image of the valve seat portion is subjected to image processing. For this reason, the position of the valve seat portion with respect to the processing position is accurately calculated, and the position of the valve seat portion is adjusted based on the calculation result. Therefore, even if thermal deformation is induced in the cylinder head by laser irradiation, each valve seat portion can be accurately positioned with respect to the processing position. Thereby, the build-up process of the valve seat part can be performed with high accuracy and good.

  FIG. 1 is a schematic perspective view of a laser cladding apparatus 10 that is a laser cladding apparatus for a valve seat portion according to an embodiment of the present invention, and FIG. 2 is a side explanatory view of the laser cladding apparatus 10.

  FIG. 3 shows the cylinder head 12 that is built up by the laser cladding apparatus 10. The cylinder head 12 is, for example, a four-cylinder engine (internal combustion engine), and each cylinder has valve seat portions 16a and 16b around two supply valve holes 14a and 14b and two exhaust valves. Valve seat portions 20a and 20b are provided around the valve holes 18a and 18b.

  As shown in FIGS. 1 and 2, the laser cladding apparatus 10 melts and solidifies the copper alloy powder 24 by irradiating the semiconductor laser 22 to the valve seat portions 16 a and 16 b and the valve seat portions 20 a and 20 b of the cylinder head 12. A laser oscillation mechanism unit 26 is provided.

  The cylinder head 12 is made of an aluminum alloy and is reduced in weight. The copper alloy powder 24 is an alloy powder based on copper and nickel, and is an atomized powder.

  The laser cladding apparatus 10 supports the cylinder head 12 and conveys the valve seat portions 16a, 16b, 20a and 20b to a processing position where the semiconductor laser 22 is irradiated, and the valve seat portions 16a, 16b, 20a and The mounting drive mechanism 28 that can rotate about the center of the processing surface 20b as a rotation axis, the imaging mechanism 30 that images the valve seat portions 16a, 16b, 20a, and 20b disposed at the processing position, and the imaging mechanism 30 Image processing is performed on the captured images of the valve seats 16a, 16b, 20a and 20b, and the positions of the valve seats 16a, 16b, 20a and 20b are calculated based on the calculation results. And an adjustable control mechanism 32. The control mechanism 32 performs drive control of the entire laser cladding apparatus 10.

  The mounting drive mechanism 28 is configured such that when the cylinder head 12 is in a predetermined angular attitude, that is, when the processing surfaces of the valve seat portions 16a, 16b, 20a, and 20b are arranged at the processing position, the processing surface faces the horizontal plane. A first stage (moving base) 36 and a second stage (moving base) 38 for moving the mounting base 34 in the orthogonal biaxial directions (arrow A direction and arrow B direction), And a rotary table 40 that rotates the cylinder head 12 on the mounting table 34 about the axis RO.

  In the vicinity of the laser oscillation mechanism portion 26, a powder supply nozzle 42 that supplies the copper alloy powder 24 to the valve seat portions 16a, 16b, 20a, and 20b corresponding to the processing position, and argon gas is supplied toward the processing position. Gas nozzle 44 is disposed. The laser oscillation mechanism unit 26, the powder supply nozzle 42, and the gas nozzle 44 can be moved up and down and horizontally moved as a unit.

  The imaging mechanism 30 includes an illumination unit 46 that irradiates the valve seats 16a, 16b, 20a, and 20b irradiated with the semiconductor laser 20 at the processing position, and the valve seat unit 16a that is disposed at the processing position. It has a solid-state image sensor that images 16b, 20a and 20b, for example, a CCD camera 48.

  The illumination unit 46 includes a halogen light source 50, for example. The CCD camera 48 is disposed on an extension line of the rotation axis RO of the placement drive mechanism 28. An image picked up by the CCD camera 48 is displayed on a monitor 52 connected to the control mechanism 32.

  The operation of the laser cladding apparatus 10 configured as described above will be described below.

  First, as shown in FIG. 4, the master work 60 is placed on the placement table 34. The reference valve hole 62 provided in the master work 60 is arranged corresponding to the irradiation position (processing position) of the semiconductor laser 22.

  Therefore, the illumination unit 46 constituting the imaging mechanism 30 irradiates the reference bulb hole 62 with the illumination light L introduced from the halogen light source 50, and the CCD camera 48 images the reference bulb hole 62. An image captured by the CCD camera 48 is sent to the monitor 52.

  Therefore, the control mechanism 32 stores the center of the reference valve hole 62 of the master work 60 displayed on the monitor 52, that is, the position of the master center MC. At that time, the position and diameter of the reference valve hole 62 are detected, and the pixel and distance are converted based on the number of pixels of the reference valve hole 62 at the time of photographing.

  As described above, after the calibration of the control mechanism 32 is performed based on the master workpiece 60, the master workpiece 60 is removed from the mounting table 34, while the cylinder head 12, which is the workpiece, is mounted on the mounting table 34. Retained. Then, under the action of the control mechanism 32, the first stage 36 and the second stage 38 constituting the placement drive mechanism 28 are driven. For this reason, for example, the valve seat portion 16a of the cylinder head 12 is arranged on an extension line of the rotation shaft RO corresponding to the processing position, and the processing surface of the valve seat portion 16a is arranged in the horizontal direction.

  Next, as shown in FIG. 2, the copper alloy powder 24 is supplied from the powder supply nozzle 42 to part of the periphery of the valve seat portion 16 a, and argon gas, which is an inert gas, is jetted from the gas nozzle 44. . In this state, the semiconductor laser 22 is irradiated from the laser oscillation mechanism unit 26 and the rotary table 40 is rotated.

  As a result, the supply position of the copper alloy powder 24 and the irradiation position of the semiconductor laser 22 move relative and annularly along the periphery of the valve seat portion 16a, and the molten pool of the copper alloy powder 24 moves annularly. Furthermore, a build-up layer is formed around the valve seat portion 16a by rotating the turntable 40 at least once.

  After the build-up process of the valve seat portion 16a is completed, the irradiation of the semiconductor laser 22 is stopped and the second stage 38 is driven. Accordingly, the cylinder head 12 is moved by a predetermined distance in the cylinder arrangement direction (in the direction of arrow A in FIG. 1) integrally with the mounting table 34, and the valve seat portion 16b is arranged corresponding to the irradiation position of the semiconductor laser 22. .

  In this case, in the present embodiment, when the valve seat portion 16b is arranged corresponding to a preset processing position (irradiation position), the image of the valve seat portion 16b at the processing position via the imaging mechanism 30. Is imaged. An image of the valve seat portion 16b is displayed on the monitor 52.

  As shown in FIG. 5, in the control mechanism 32, a deviation amount and a diameter change between the center VC of the valve hole 14 b displayed on the monitor 52 and the master center MC of the reference valve hole 62 obtained by the master work 60 are changed. Calculated. A deviation amount and a diameter change from the master center MC to the center VC of the valve hole 14b are digitized by pixel-distance conversion based on the number of pixels and set as a correction position on the orthogonal biaxial coordinates of the mounting drive mechanism 28. Is done.

  As a result, the center VC of the valve hole 14b of the valve seat portion 16b is accurately arranged on the axis RO of the rotary table 40, and the valve seat portion 16b is subjected to the overlaying process in the same manner as the valve seat portion 16a. Is given. At this time, the valve seat portion 16b is positioned with high accuracy corresponding to the irradiation position of the semiconductor laser 22, and for example, even if the cylinder head 12 is thermally deformed by the irradiation of the semiconductor laser 22, the valve seat The part 16b can be accurately and reliably positioned with respect to the processing position.

  For this reason, for example, as shown in FIG. 6, a black skin residue 70 is generated after building up as shown in FIG. 6, or a member (aluminum alloy) between the valve seat portions 16 b and 20 b as shown in FIG. It is possible to reliably prevent the occurrence of poor quality parts 72 such as melting and cracking of the steel. Therefore, it is possible to obtain the effect that the overlaying process of the valve seat portions 16a and 16b is performed with high accuracy and goodness and the efficient overlaying process is performed.

  Similarly, the exhaust-side valve seat portions 20a and 20b also have an advantage that the above-mentioned quality defects are reliably prevented and a high quality and good build-up process is achieved.

It is a schematic perspective explanatory drawing of the laser cladding apparatus which is a laser cladding apparatus of the valve seat part which concerns on embodiment of this invention. It is side surface explanatory drawing of the said laser cladding apparatus. It is explanatory drawing of a cylinder head. It is explanatory drawing of the calibration of the said laser cladding apparatus. It is explanatory drawing of the center shift | offset | difference of the said valve seat part. It is explanatory drawing of the black skin remaining in the said valve seat part. It is explanatory drawing of the quality defect site | part of the said valve seat part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Laser clad apparatus 12 ... Cylinder head 14a, 14b, 18a, 18b ... Valve hole 16a, 16b, 20a, 20b ... Valve seat part 22 ... Semiconductor laser 24 ... Copper alloy powder 26 ... Laser oscillation mechanism part 28 ... Mounting drive Mechanism 30 ... Imaging mechanism 32 ... Control mechanism 34 ... Mounting table 36, 38 ... Stage 40 ... Rotary table 42 ... Powder supply nozzle 44 ... Gas nozzle 46 ... Illumination unit 48 ... CCD camera

Claims (4)

A laser build-up device for a valve seat that melts and solidifies by supplying a laser to the metal powder while supplying metal powder to the valve seat portion of the cylinder head,
A mounting drive mechanism that supports the cylinder head, conveys each valve seat portion to a processing position irradiated with the laser, and is rotatable about the center of the processing surface of each valve seat portion as a rotation axis;
An imaging mechanism for imaging the valve seat portion disposed at the processing position;
A control mechanism that performs image processing on a captured image by the imaging mechanism, calculates the position of the valve seat portion that has been imaged, and adjusts the position of the valve seat portion based on the calculation result;
A laser cladding apparatus for a valve seat portion comprising: 2. The laser cladding apparatus according to claim 1, wherein the mounting drive mechanism includes a mounting table on which the cylinder head is mounted at a predetermined angular attitude;
By moving the mounting table, each valve seat provided in the cylinder head, a moving table that selectively arranges at the processing position;
A turntable capable of rotating the movable table;
A laser cladding apparatus for a valve seat portion comprising: 3. The laser cladding apparatus according to claim 1, wherein the imaging mechanism includes an illumination unit that irradiates illumination light to the valve seat unit irradiated with the laser;
A solid-state imaging device that images the valve seat portion disposed at the processing position;
A laser cladding apparatus for a valve seat portion comprising:   4. The laser beam overlaying apparatus according to claim 3, wherein the solid-state imaging device is disposed on an extension line of a rotation shaft of the placement drive mechanism.

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